Shorter period days during ttc #2. What!?

It's been 2 months ttc#2. Today, I'm on my 3rd day of my period. My period ended on the second day and then spotted today. My normal length of period are 6 days. Why are my length of period days shortening by each passing months. My period is now irregular. This has never happened to me. What is happening to me? I did some research. I'll be asking my doctor next. Anyone drop me a hint if you know.